Near-threshold $K^{\ast }(892{)}^{+}$ meson production in the interaction of ${\pi }^{-}$ mesons with nuclei

Abstract

We study the inclusive strange vector meson $K^{\ast }(892{)}^{+}$ production in ${\pi }^{-}A$ reactions at near-threshold laboratory incident pion momenta of 1.4--2.0 GeV/c within a nuclear spectral function approach. The approach accounts for incoherent primary ${\pi }^{-}$ meson--proton ${\pi }^{-}p\to K^{\ast }(892{)}^{+}{\Sigma }^{-}$ production processes as well as the influence of the scalar $K^{\ast }(892{)}^{+}$--nucleus potential (or the $K^{\ast }(892{)}^{+}$ in-medium mass shift) on these processes. We calculate the absolute differential and total cross sections for the production of $K^{\ast }(892{)}^{+}$ mesons off carbon and tungsten nuclei at laboratory angles of 0${}^{\circ }$--45${}^{\circ }$ and at these momenta within five scenarios for the above shift. We show that the $K^{\ast }(892{)}^{+}$ momentum distributions and their excitation functions (absolute and relative) possess a high sensitivity to changes in the in-medium $K^{\ast }(892{)}^{+}$ mass shift in the low-momentum region of 0.1--0.6 GeV/c. Therefore, the measurement of such observables in a dedicated experiment at the GSI pion beam facility in the near-threshold momentum domain will allow to get valuable information on the $K^{\ast }(892{)}^{+}$ in-medium properties.

Comments: 16 pages, will be published in Chinese Physics C. arXiv admin note: text overlap with arXiv:1910.02755